Pulse detonation device for a coal burning system

ABSTRACT

A pulse detonation coal burner includes a burner body having an inlet and an outlet, and a fuel introduction system coupled to the inlet of the burner body. The fuel introduction system is configured and disposed to introduce at least one fuel into the burner body. A pulse detonation device is operatively coupled to the burner body. The pulse detonation device is configured and disposed to introduce a pulse detonation wave into the burner body to ignite the at least one fuel.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to coal burning systems and, more particularly, to a pulse detonation device for a coal burning system.

Many electric power generating systems employ pulverized coal as a fuel. A pulverized coal fired boiler generates thermal energy by burning pulverized coal (powdered coal, coal dust). The thermal energy is used to heat a fluid and create steam that is employed to drive a turbine. Conventional coal burning systems introduce pulverized coal into one or more burners. The coal combusts releasing thermal energy. Pulverized coal is typically introduced into the burner by a mechanical feed system that sends raw coal to a pulverizer and then to the burner(s). In such systems, the pulverized coal is fed/distributed into coal pipes located within the burner(s). A typical system employs a number of feeders and pulverizers to establish an even distribution of pulverized coal to the burners. Feeder system efficiency, i.e., the ability to control coal distribution and maintain proper particle size of the pulverized coal is a factor in emission levels and combustion efficiency for a particular coal burning system.

BRIEF DESCRIPTION OF THE INVENTION

According to one aspect of an exemplary embodiment, a pulse detonation coal burner includes a burner body having an inlet and an outlet, and a fuel introduction system coupled to the inlet of the burner body. The fuel introduction system is configured and disposed to introduce at least one fuel into the burner body. A pulse detonation device is operatively coupled to the burner body. The pulse detonation device is configured and disposed to introduce a pulse detonation wave into the burner body to ignite the at least one fuel.

According to another aspect of the exemplary embodiment, a coal burning furnace system includes a coal burning furnace including a furnace body including a heat exchange system, and an energy conversion system operatively connected to the heat exchange system. The energy conversion system is configured and disposed to transform thermal energy from the heat exchange system to mechanical energy. A pulse detonation coal burner is fluidly connected to the coal burning furnace. The pulse detonation coal burner includes a burner body having an inlet and an outlet, and a fuel introduction system coupled to the inlet of the burner body. The fuel introduction system is configured and disposed to introduce at least one fuel into the burner body. A pulse detonation device is operatively coupled to the burner body. The pulse detonation device is configured and disposed to introduce a pulse detonation wave into the burner body to ignite the at least one fuel.

According to yet another aspect of the exemplary embodiment, a method of burning pulverized coal for a coal burning system includes introducing an amount of coal into a burner body, guiding an amount of air into the burner body, mixing the amount of coal and the amount of air to form a combustible fuel mixture, and igniting the combustible fuel mixture with a pulse detonation wave generated by a pulse detonation device.

These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWING

The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic diagram of a coal burning system including a coal burning furnace fired by a pulse detonation coal burner system in accordance with an exemplary embodiment;

FIG. 2 is a perspective view of a pulse detonation coal burner system coupled to a coal burning furnace in accordance with an exemplary embodiment; and

FIG. 3 is a schematic cross-sectional view of the pulse detonation coal burner system of FIG. 2.

The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1-3, a coal burning system in accordance with an exemplary embodiment is indicated generally at 2. Coal burning system 2 includes a coal burning furnace/boiler 4 having a heat exchange system or burner 8. Burner 8 transfers heat into a working fluid that is passed to an energy conversion system (not shown). The energy conversion system is typically coupled to a powered member such as a generator, a pump, or the like. The energy conversion system converts thermal energy from a working fluid produced in boiler 4 into mechanical, rotational, energy used to operate the powered member. Products of combustion from burner 8 pass to an air heater 10, flow to an emissions control device 12 and are directed to a stack 14 by a fan 16.

Thermal energy is input into the working fluid by a heat directed toward burner 8 developed by burning powdered or pulverized coal. In accordance with the exemplary embodiment, boiler 4 is coupled to a pulse detonation coal burner system 40. Pulse detonation coal burner system 40 includes a burner body 44 having an inlet 46 that is fluidly coupled to an outlet 47. Outlet 47 is fluidly connected to coal burning furnace 4. Fuel, in the form of pulverized coal and air, is introduced into inlet 46 through a fuel introduction system 54. Fuel introduction system 54 includes a fuel supply conduit 56 having a first end or inlet portion 58 that extends to a second end or outlet portion 59 through an intermediate portion 60 that defines a fuel passage 62. Fuel supply conduit 56 delivers pulverized coal from a coal pulverizing device 70 that is coupled to a coal silo 72. Pulverized coal and air are introduced into inlet portion 58 and passed along fuel passage 62 toward outlet portion 59. Combustion air is introduced to inlet 46 outside of fuel passage 62. To improve combustion of the pulverized fuel and air mixture, a plurality of spin vanes, two of which are indicated at 65 and 66 are typically arranged within burner body 44. Spin vanes 65 and 66 impart a swirl to the pulverized fuel and air mixture entering boiler 4. The pulverized coal mixes with the air to form a combustible mixture that is ignited by a pulse detonation device 80 to form a flame front that is directed through outlet 47 of burner body 44 into coal burning furnace 4

Pulse detonation device 80 includes a body member 83 having a first end or inlet section 86 that extends to a second end or outlet section 87 through an intermediate section 89. In the exemplary embodiment shown, pulse detonation device 80 includes an outlet tube 91 operatively coupled body member 83 at outlet section 87. In accordance with one aspect of the exemplary embodiment, outlet tube 91 extends into fuel supply conduit 56 and terminates at an outlet 92. With this arrangement, outlet is selectively positioned relative to outlet portion 59 in order to achieve a desired combustion of the pulverized coal and air. At this point it should be understood that although shown positioned within fuel supply conduit 56, outlet tube 91 could extend directly into burner body 44. Also, while shown with a single pulse detonation device coupled to burner body 44, it should be understood the particular location and number of pulse detonation devices can vary. That is, multiple pulse detonation devices could be arrayed inside or about burner body 44 in order to achieve desired combustion characteristics. Also, it should be understood that a diameter of outlet tube 91 could vary depending upon desired combustion characteristics.

In further accordance with the exemplary embodiment, pulse denotation device 80 is fluidly coupled to a pulse detonation fuel system 94. Pulse detonation fuel system 94 includes a pulse detonation fuel supply 96 that is fluidly coupled to inlet section 86 through a pulse detonation fuel supply pipe 97. Pulse detonation fuel supply 96 is shown to include a pressure regulator 98 that regulates pulse detonation fuel pressure delivered to pulse detonation device 80. Pulse detonation fuel system 94 is also shown to include an air supply system 100 that received pressurized air from a compressor or fan 102. Air supply system 100 is fluidly connected to inlet section 86 through an air supply pipe 104. Air supply pipe 104 is shown to include an air drier 107, a pressure regulator or control valve 109 as well as a pair of service valves 111 and 112. Air supply pipe 104 is also shown to include an electronic control valve 114 that is operatively coupled to a controller 117. Controller 117 is also operatively coupled to a fuel control valve 120 arranged at inlet section 86.

With this arrangement, controller 117 establishes a desired fuel/air mixture that is passed to pulse detonation device 80. The fuel air mixture is ignited to form a pulse detonation wave that is directed at the pulverized coal and air flowing though fuel supply conduit 56 to establish a stable flame front exiting the burner body 44. Controller 117 is also configured to set a desired frequency of the pulse detonation wave emanating from pulse detonation device 80. Controller 117 can set a desired frequency for the pulse detonation wave. The frequency of the pulse detonation wave can be controlled to aid in mixing of the pulverized coal and air. Pulse detonation wave can reach temperatures up to about 2500° F. (1371.1° C.) degrees or better. The high temperatures achievable by the use of a pulse detonation device, as well as the additional mixing of the coal and air provided by the pulse detonation wave can enable operation of the burner at conditions that lower emissions which occur during the operation of the coal burning system. That is, the use of the pulse detonation device will lower CO emissions as well as other products of incomplete combustion such as carbon in ash. The additional mixing provided by the pulse detonation wave could also lead to lower combustion stoichiometry that would result in reduced NOx emissions.

While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. 

1. A pulse detonation coal burner system comprising: a burner body having an inlet and an outlet; a fuel introduction system coupled to the inlet of the burner body, the fuel introduction system being configured and disposed to introduce at least one fuel into the burner body; and a pulse detonation device operatively coupled to the burner body, the pulse detonation device being configured and disposed to introduce a pulse detonation wave into the burner body to ignite the at least one fuel.
 2. The pulse detonation coal burner system according to claim 1, wherein the fuel introduction system is configured to guide coal into the burner body.
 3. The pulse detonation coal burner system according to claim 2, wherein the fuel introduction system is configured to guide pulverized coal and air into the burner body.
 4. The pulse detonation coal burner system according to claim 1, wherein the fuel introduction system includes a fuel supply conduit having a first end portion that extends to a second end portion through a fuel passage, the first end portion defining a fuel inlet and the second end portion defining a fuel outlet, the fuel outlet being arranged within the burner body.
 5. The pulse detonation coal burner system according to claim 4, wherein the pulse detonation device includes a body member having first end section that extends to a second end section through an intermediate section, the first end section defining an inlet section and the second end section defining an outlet section.
 6. The pulse detonation coal burner system according to claim 5, wherein the pulse detonation device includes an outlet tube fluidly connected to the body member, the outlet tube being arranged within the fuel supply conduit.
 7. The pulse detonation coal burner system according to claim 6, further comprising: a pulse detonation fuel system fluidly connected to the inlet section of the body member, the pulse detonation fuel system including a fuel supply and an air supply.
 8. The pulse detonation coal burner system according to claim 7, wherein each of the fuel supply and air supply are operatively connected to a controller that regulates delivery of air and fuel into the body member.
 9. The pulse detonation coal burner system according to claim 1, further comprising: a plurality of spin vanes arranged radially about the fuel introduction system.
 10. A coal burning furnace system comprising: a coal burning furnace including a furnace body including a heat exchange system; a pulse detonation coal burner system fluidly connected to the coal burning furnace, the pulse detonation coal burner system including a burner body having an inlet and an outlet, a fuel introduction system coupled to the inlet of the burner body, the fuel introduction system being configured and disposed to introduce at least one fuel into the burner body, and a pulse detonation device operatively coupled to the burner body, the pulse detonation device being configured and disposed to introduce a pulse detonation wave into the burner body to ignite the at least one fuel.
 11. The coal burning furnace system according to claim 10, wherein the fuel introduction system is configured to guide coal into the burner body.
 12. The coal burning furnace system according to claim 11, wherein the fuel introduction system is configured to guide pulverized coal and air into the burner body.
 13. The coal burning furnace system according to claim 10, wherein the fuel introduction system includes a fuel supply conduit having a first end portion that extends to a second end portion through a fuel passage, the first end portion defining a fuel inlet and the second end portion defining a fuel outlet, the fuel outlet being arranged within the burner body.
 14. The coal burning furnace system according to claim 10, wherein the pulse detonation device includes a body member having first end section that extends to a second end section through an intermediate section, the first end section defining a an inlet section and the second end section defining an outlet section.
 15. The coal burning furnace system according to claim 14, wherein the pulse detonation device includes an outlet tube fluidly connected to the body member, the outlet tube being arranged within the fuel supply conduit.
 16. The coal burning furnace system according to claim 14, further comprising: a pulse detonation fuel system fluidly connected to the inlet section of the body member, the pulse detonation fuel system including a fuel supply and an air supply.
 17. The coal burning furnace system according to claim 16, wherein each of the fuel supply and air supply are operatively connected to a controller that regulates delivery of air and fuel into the body member.
 18. A method of burning pulverized coal for a coal burning system, the method comprising: introducing an amount of coal into a burner body; guiding an amount of air into the burner body; mixing the amount of coal and the amount of air to form a combustible fuel mixture; and igniting the combustible fuel mixture with a pulse detonation wave generated by a pulse detonation device to form a flame front.
 19. The method of claim 18, further comprising: inducing a swirl to the combustible fuel mixture.
 20. The method of claim 19, further comprising: directing the flame front into a coal burning furnace. 